Inter-prefecture disparity in under-5 mortality: 115 year trend in Japan

[Social inequalities in under-five mortality: a systematic review]

OBJECTIVE

To identify the characteristics of the published studies on social inequalities in under-five mortality, their theoretical perspectives, axes of inequality, methods and results.

METHOD

We carried out a systematic literature review. We consulted four electronic databases and Google Scholar, for studies published between 2010 and 2018.

RESULTS

We analyzed 126 articles. In 62.7%, territory was studied as the axis of inequality, followed by socioeconomic determinants (27.8%). Neonatal, infant and under-five mortality was analyzed as an output in health in 19.0%, 49.2% and 32.3%, respectively. It predominated ecological (62.7%) and longitudinal (50.0%) studies. Significant reductions in mortality rates were found, however, the decline was not homogeneous among subpopulations.

CONCLUSIONS

The literature reports a marked decrease in under-five mortality; however, the gaps between different axes of inequality continue and in some cases they have increased. Gaps varied according to time, place, axis of inequality and type of mortality analyzed.

Analysis of association between low birth weight and socioeconomic deprivation level in Japan: an ecological study using nationwide municipal data

BACKGROUND

Several international studies have indicated an association between socioeconomic deprivation levels and adverse birth outcomes. In contrast, those investigating an association between socioeconomic status and low birth weight using nationwide data are limited in Japan. In this study, we investigated an association between municipal socioeconomic deprivation level and low birth weight by an ecological study.

METHODS

Nationwide municipal-specific Vital Statistics data from 2013 to 2017 were used. We calculated the low birth weight rate and standardized incidence ratio (SIR) for low birth weight for each municipality and plotted them on a Japanese map. Furthermore, the correlation coefficient between them and the deprivation level were calculated. In addition, a spatial regression model including other municipal characteristics was used to investigate an association between low birth weight and the deprivation level.

RESULTS

Municipalities with relatively high SIR for low birth weight were dispersed across all of Japan. The correlation coefficient between the socioeconomic deprivation level and low birth weight rate was 0.196 (p-value < 0.001) among municipalities, and that between the socioeconomic deprivation level and the SIR for low birth weight was 0.260 (p-value < 0.001). In addition, the spatial regression analysis showed the deprivation level was significantly and positively associated with low birth weight.

CONCLUSIONS

The socioeconomic deprivation level and low birth weight were positively associated, and a further study using individual data is warranted to verify reasons for the association.

Contribution of the Technical Efficiency of Public Health Programs to National Trends and Regional Disparities in Unintentional Childhood Injury in Japan

To achieve the Sustainable Development Goals, strengthening investments in health service inputs has been widely emphasized, but less attention has been paid to tackling variation in the technical efficiency of services. In this study, we estimated the technical efficiency of local public health programs for the prevention of unintentional childhood injury and explored its contribution to national trend changes and regional health disparities in Japan. Efficiency scores were estimated based on the Cobb-Douglas and translog production functions using a true fixed effects model in a stochastic frontier analysis to account for unobserved time-invariant heterogeneity across prefectures. Using public data sources, we compiled panel data from 2001 to 2017 for all 47 prefectures in Japan. We treated disability-adjusted life years (DALYs) as the output, coverage rates of public health programs as inputs, and caregivers' capacity and environmental factors as constraints. To investigate the contribution of efficiency to trend changes and disparities in output, we calculated the predicted DALYs with several measures of inefficiency scores (2001 average, yearly average, and prefecture-year-specific estimates). In the translog model, mean efficiency increased from 0.62 in 2001 to 0.85 in 2017. The efficiency gaps among prefectures narrowed until 2007 and then remained constant until 2017. Holding inefficiency score constant, inputs and constraints contributed to improvements in average DALYs and widened regional gaps. Improved efficiency over the years further contributed to improvements in average DALYs. Efficiency improvement in low-output regions and stagnated improvement in high-output regions offset the trend of widening regional health disparities. Similar results were obtained with the Cobb-Douglas model. Our results demonstrated that assessing the inputs, constraints, output, and technical efficiency of public health programs could provide policy leverage relevant to region-specific conditions and performance to achieve health promotion and equity.

Differences in Rates of Low Birth Weight among Prefectures in Japan: An Ecological Study Using Government Statistics Data

The differences in the rates and trends of the overall low birth weight and term low birth weight in recent years are unknown for the Japanese prefectures. In this ecological study, we revealed the rates for each prefecture and investigated the factors affecting the regional differences in these outcomes. Aggregated vital statistics data from 2007 to 2019 were obtained from the Ministry of Health, Labour, and Welfare in Japan. The association between the outcomes and the variables, including the infants’ birth characteristics, medical characteristics, and socioeconomic characteristics of the prefectures, were analyzed. An analysis of repeated-measures data was conducted using the data from 2013 and 2018 for each prefecture. The trend for the rates of overall low birth weight and term low birth weight over the years differed among the prefectures. Moreover, the proportions of multiple births and lean (body mass index <18.5 kg/m2) and obese (body mass index ≥25.0 kg/m2) women had a statistically significant positive association with both the overall low birth weight rate and the term low birth weight rate among the prefectures. It was suggested that to resolve the difference in these outcomes among the prefectures, being obese or underweight needs to be addressed in mothers.

Secular trends in longevity among people with Down syndrome in Japan, 1995-2016

BACKGROUND

Life expectancy in Japan has increased dramatically and is one of the longest in the world. However, the changes in lifespan in Japanese individuals with congenital diseases remain unknown. We investigated secular changes in the lifespan of people with Down syndrome over the last 20 years.

METHODS

We observed secular trends in the number of stillbirths, deaths and the mortality rates at ages 20, 40, and 60 among all deaths registered with Down syndrome as the cause of death (ICD10 code: Q90) in the Japan national death registry database between 1995 and 2016. Changes in the median age at death between 1995-2005 and 2006-2016 were investigated based on sex and history of surgery.

RESULTS

We identified 240 stillbirths and 1,099 deaths in this period. The annual number of stillbirths and deaths above the age of 1 year increased, whereas the number of deaths below 1 year did not change. The proportional mortality indicator at ages 20, 40, and 60 increased from 21.7%, 11.7%, and 1.7% in 1995 to 69.9%, 66.7%, and 36.6% in 2016, respectively. The median age at death was higher in females, individuals without a surgical history, and deaths occurring in 2006-2016. The median age at death increased over the period in those without a surgical history.

CONCLUSIONS

The age at death among people with Down syndrome has increased over the last 20 years, with currently 1 in 3 persons living over 60 years, necessitating adequate social welfare services in this aging population.

Infant Mortality Rates for Farming and Unemployed Households in the Japanese Prefectures: An Ecological Time Trend Analysis, 1999-2017

Background

Recent research suggests that Japanese inter-prefecture inequality in the risk of death before reaching 5 years old has increased since the 2000s. Despite this, there have been no studies examining recent trends in inequality in the infant mortality rate (IMR) with associated socioeconomic characteristics. This study specifically focused on household occupation, environment, and support systems for perinatal parents.

Methods

Using national vital statistics by household occupation aggregated in 47 prefectures from 1999 through 2017, we conducted multilevel negative binomial regression analysis to evaluate occupation/IMR associations and joinpoint analysis to observe temporal trends. We also created thematic maps to depict the geographical distribution of the IMR.

Results

Compared to the most privileged occupations (ie, type II regular workers; including employees in companies with over 100 employees), IMR ratios were 1.26 for type I regular workers (including employees in companies with less than 100 employees), 1.41 for the self-employed, 1.96 for those engaged in farming, and 6.48 for unemployed workers. The IMR ratio among farming households was 1.75 in the prefectures with the highest population density (vs the lowest) and 1.41 in prefectures with the highest number of farming households per 100 households (vs the lowest). Joinpoint regression showed a yearly monotonic increase in the differences and ratios of IMRs among farming households compared to type II regular worker households. For unemployed workers, differences in IMRs increased sharply from 2009 while ratios increased from 2012.

Conclusions

Inter-occupational IMR inequality increased from 1999 through 2017 in Japan. Further studies using individual-level data are warranted to better understand the mechanisms that contributed to this increase.